Taken with the 159th overall pick, Rainey was the school's second player taken in this year's draft. Defensive tackle Jaye Howard went before him, claimed by the Seattle Seahawks in the fourth round earlier in the day Saturday.

Rainey finished his career with 19 starts in 52 games at Florida. He totaled 2,464 yards rushing, good for ninth all-time at the school, and averaged 6.2 yards per carry. The team's MVP in 2011, Rainey had 69 career receptions for 795 yards.

He was a key contributor on special teams, setting a school and SEC record for career blocked punts with six.

In Pittsburgh, Rainey joins fellow former Gators Marcus Gilbert and Maurkice Pouncey. The offensive linemen blocked for Rainey while they were still at UF.

"It will be good for him to reunite with Maurkice -- he is someone Chris has spent a great deal of his life around," UF coach Will Muschamp said. "He will do whatever he is asked and is eager to begin his professional career."

Speaking to ESPN during the draft, Steelers coach Mike Tomlin made it known that he had many different plans for using the explosive Rainey's speed.

"(He'll be) in the backfield, outside the backfield, in the return game. He's an explosive player in the SEC," Tomlin said. "When you're fast on the SEC fields, chances are, you're going to be fast on the NFL fields."

Rainey's speed was what made him valuable in ESPN analyst Mel Kiper, Jr.'s eyes before the draft.

"When you look at Rainey, I think there's speed and versatility," Kiper said, "and he gives you the ability to do some things with him in this game."